Casing guide



April 13, 1965 J, E, HALL, 5R 3,177,946

cAsING GUIDE Filed July 18, 1962 2 Sheets-Sheet l JNVENToR. leise E. Ha@ 5f;

BY l

/J TTORNEKS.

April 13, 1965 J. E. HALL, SR 3,177,946

CASING GUIDE Filed July 18, 1962 2 Sheets-Sheet 2 INVENTOR. M255@ E Ha@ 5f.'

United States Patent() 3,177,946 CASING GUIDE .lesse E. Hall, Sr., Weatherford, Tex., assigner to Trojan, Inc., Panama, Panama, a Panamanian corporation Filed July 18, 1962, Ser. No. 210,722 6 Claims. (Cl. 16o-241) This invention relates generally to'oil well casing guides and refers more particularly to improved guides for use in close tolerance and multiple string wells.

There are many Well completion situations today where the close tolerance which exists between the exterior of the casing and the well wall imposes stringent operating requirements on the devices used on the casing to center it in the well bore and to aid in effecting a good cement job. This is particularly true in wellsof extreme depth. In such wells the annular space between the casing and bore is of small thickness and anything applied to the exterior of the casing must be of correspondingly small thickness in order to insure that the casing can be lowered into the bore with the minimum of interference. On the other hand, because of the depth of the well and the forces which may be imposed, any exterior appliances must concurrently be extremely strong. A third requirement is that they furthermore must provide suicient open space around the casing as to permit the free circulation past the appliance of mud and cement during the cementing operation.

One of the important objects of the present invention is to provide a well casing guideY which, due to its manner of construction and assembly, uniquely meets all of the requirements heretofore set forth for close tolerance wells. Not only does the guide according to my invention occupy a minimum of the annulus surrounding the casing, but also it is of exceptional strength and is capable of eiectively absorbing end loads of great magnitude without destruction.

A further object'of the invention is to provide a casing guide of the character described which has a construction such that'its ability to holdgthe casing away from contact with the well'bore is greatly improved over conventional 'guides and centralizers.

Yet another object of the invention is to provide a casing guide having the foregoing characteristics and which is so constructed that itsrnaximurn effective diameter can be held within the outside diameter of the couplings between successive lengths ofcasing. Through such anV arrangement I have made it possible for the greatest loads caused by resistance to entry of the casing into the bore to be absorbed atthe casing couplings rather than in thecasing guide, the couplings thus in effect clearing the way for the casing guides.

Another object of the invention is to provide a Vcasing guide of the character described and which has particular usefulnessin connection with multiple string well completion where a plurality of tubings are placed in a single well bore. .In the form of the invention adapted for multiple string completion I provide in an essentially six bow guide or Vcentralizer an arrangement wherein the effective bow area for engaging the bore is substantially doubled and wherein the end loads on the guide are absorbed in the spring-like bows themselves rather than `in any connections between the bows .and their attaching collars. The multiple string guide is uniquely designed to eectively maintain the strings apart and to prevent intertwining of the strings and clogging of the annulus.4

Still another object of the invention is to provide casing guides having the foregoing operational yadvantages and which are susceptible of-manufacturenand Vassembly at relatively low cost.

ICC

Other and further objects of the invention together with the features of novelty appurtenant thereto will appear in the course ofthe following description.

In the accompanying drawings which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals indicate like parts in the various views:

FIG. 1 is a side elevational view of a typical close tolerance casing guide embodying the features of the invention; Y

FIG. 2 isV an end view taken from the upper end of FIG. 1;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2 in the direction of the arrows;

FIG. 4 is an enlarged fragmentary sectional view taken along the line 4 4 of FIG. 1 in the direction of the arrows;

FIG. 5 is a side elevational View of a modified form of the invention;

FIG. 6 is a sectional view taken generally along line 6--5 of FIG. 5 in the direction of the arrows; and

FIG. 7 is an end view taken from the upper end of FIG. 5.

Referring to the drawings and initially to the form of the invention shown in FIGS. 1-4, inclusive, the guide generally comprises a pair of circular collars 10 between which extend at uniformly spaced intervals the guide or spring members 11. Collars 10 are Aaxially aligned and are identical in construction, the lower collar simply being inverted in position.

Each collar is formed from relatively light gauge sheet metal, for example, a good quality steel. The, collar is constructed from a strip of such material bent to the circular form and having its ends joined by a connection which includes inter-engaging finger-like projections, later to be described, vertically apertured to receive therethrough a iiat pin 12. The material of which the collars are formed is of such thickness and quality that upon removal of the pin 12, the collar can be opened sutlciently as to permit its lateral application to a well casing (not shown) following which the pin is reinserted to complete the installation.

As shown in the drawing, each collar has formed therein at the opposed ends inwardly depressedcircumferential ribs 13, 14. The inside diameter of the collar at the apices of the ribs approximates the outside diame ter of the casing on which the appliance is to be mounted, being only enough greater as to permit free sliding movement of the collars longitudinally of the casing.

The wall ot the collar between the ribs 12, 13 is formed i in a series of Vbands 15, 16, 17 which are progressively stepped inwardly to provide annular shoulders 15a, 16a, running circumferentially of the collars. The band 15 is of the greatest inside diameter.

The guide members or springs 11 each comprise elongate bars of rectangular cross section formed from good quality spring steel. They are so constructed as to provide essentially straight, longitudinally aligned upper and lower end portions 11a, 11b, symmetrical outwardly bowed upper and lower bow sections 11C, 11d, land the central zone 11e which connects the outwardly bowed sections.

The central zone, in adition to being located closer to the axis of the guide than the bow sections, is formed with what may best be termed an elongate S-shaped lateral The respective end portions 11a, 11b of each guidev member are disposed on the inside of the collar with the outer surface of the end portion abutting and secured as through.

g the inside faces thereof are approximately the same radial distance from the central axis vas theA apices of the ribs.

The bowed sections 11d, 11e proceed from the inside of the collars to the outside thereof through registering rectangular apertures 19 formed largely in the central band 1,6, but extending also into the shoulder portions a, 16a. The apertures are of such length and width as to permit the guide member to be inserted loosely there- In fact, the side edges of the aperture should be spaced slightly away from the adjacent longitudinal edges of the guide member and that edge of the aperture adjacent the emergent bow section suiiiciently spaced from the inside surface thereof so that there is freedom in the bow to flex inwardly a limited amount before striking same. n

The interlocking end connecting portions are formed as extensions 2da, 21a on members indicated generally by Vreference'nun'rerals 249 and 21, and comprising doubled back strips of metal out away along the fold line. to provide the finger-like interlocking portions. The confronting portions of the plies in extensions 20a, 21a are spread apart suiiiciently as to form loops permitting insertion of the pin 12. The plies of the :members 2), 21 to the side of the interlocking portions 2da, 21d, typified at Ztlb, 20c in FIG. 4, are joined to one another and to thecnds of the collar by spot welds as at 22. it will be noted that the plies are fiat with one section inside the collar underlying bands 15, 1o and the remaining section outside on the exterior Iband 17. The band 15a is iiattened adjacent members 20, 21 and such member emerges to the exterior of band 17 through a slot having parallel edges 23, 24

- (see FIG. 4) lformed by cutting away the band 16a `at these locations.

In the operation of the tool as thus far described, it is applied Vto the casing with the collars 1t? encircling the casing .and with the uppermost collar disposed below a casing joint or couplinv or below a conventional stop collar on the casing. As the casing is moved into and down the well bore the tool is ineffect pushed ahead of the casing joint or stop collar as the case may be. Should the tool encounter any resistance along the way the `thrust load imposed is carried primarily by the guide members 11 rather than yin the welds which secure the guide members to the collars. This is because the abutting relationship between the rib 13 and the end of the guide memf ber provides a direct transmission of the thrust to the r guide members. Thus, there is little or no danger of the The ribs 13, 14 and stepped configuration of the collar aid materially in obtaining a structure of satisfactory strength with a minimum thickness material. The apertures 19 provide pressure relief outlets for mud or cement trapped inside the collar and are believed to contribute considerably to aiding in free circulation of mud and cement past the tool.

The manner of construction of the tool is such that it lends itself to rapid and facile assembly of the guide members 11 with collars 1t) during manufacture. The apertures 19 provide a means of quickly indexing the guide members on the collars with theguide members at the proper spacing and the collars in the proper relationship therewith.

FIGS. 5-7, inclusive, show a modified formof the invention having a particular utility in conjunction with multiple string wells, although it has advantage also in connection with ordinary completion operations as hereinbefore set forth. The collars 110 are substantially identical with those describedin` the preceding embodiment. However, the guide members 111 are differently formed.

As in the preceding embodiment, the end portions Illa and111b are secured to the collars adjacent the end ribs 113 and against the large diameter band 115. The bowed sections111c and 111e' emerge from the inside of the collar through like apertures 119. However, as best seen by examining the foremost guide member of FIG. 5, the end portions 111a and 11117, as Well as their associated bowed sections 111C and 111d of each guide member, are offset a substantial distance, being connected by an intermediate cornplexly bent section 111e. This section traverses laterally between the bowed section and at the same time dips inwardly toward the central axis of the units to provide an innermost'casing contacting surface 1111 Whose long axis is inclined-substantially from a longitudinal plane through the axis of the unit.

The offset of the bowed sections 111C, 111d is substantially equal to one-half the circumferential spacing between the common end portions of the guides. As may f best be seen in FIG. 7, this providesthe tool with the end-wise equivalent of double the actual number of guide members present.' Each bowed section 111C or 111d thus guide members being separated Vfrom the collars even under the greatest of loads Y The provision of the guide'members with the double bow configuration and the oit-set or jogged central S- shaped portions also assists greatly incombining the function of providing a strong centering support for the casing with the function of ability to resist end loads on the tool of a high order. Any inward pressure on the guide mem-bers will be resisted at three points, namely, by

contact of the end portions 11a, 11b, and central surface longitudinal end loads While still preserving Contact at 117c with the casing.

When the guide is used as a well scraping appliancefin Y addition to its function as a centralizer, as taught in'Hall Patent 2,731,816, the S-shaped portions assist materially in the cleaning of mud and/or cement from Vthe casing while the casing is reciprocated. f

in effect acts an an independent guide member. By virtue of the offset relationship between the upper and the lower bow sections on each guide member, I am able to obtain a high degree of surface area acting to center the casing inthe bore and 'tokeep it spaced from adjacent casings while still leaving sulicient 110W space through the annulus as to promotegood circulation. The large number of bow sections'insures that upon relative longitudinal movement'of adjacent casings and a multiple string completion, the couplings of the casings will freely pass since the casings are held off from'one another a distance at least equal to and actually somewhat greater than the radial thickness ofV the coupling. An adjacent casing ork tubing, even though its diameter may be less than the spacing between the upper bow sections 111e, cannot become nested therebetween since itzwill be held off by the oifset lower sections 4111d whose axes lie intermediate ther upper bow sections. Y

From the foregoing it will'be seen that this invention is VVonewell adapted to attain all of the ends and objects hereinabove set forth together with other advantages which are vobvious and-which are inherent to the structure.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to otherA features and subcombinations. This is contemplated by and iswithin the `scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and notin a limiting sense.

Having thus described my invention, I claim:

1. In a casing guide adapted for mounting on a well casing, the combination of a pair of circular collars axially aligned and spaced from one another, a plurality of guide members extending between said collars and each having its opposed ends connected respectively with said collars, each collar comprising a sheet metal shell of substantially uniform thickness having progressively inwardly stepped bands formed in the wall with the band of the greatest inside diameter at the outer end of the collar and joined to the adjacent band by a circumferential band providing an annular shoulder, the respective end portions of the guide members lying adjacent and secured to the inside of said outer band with the extreme end of the guide at each collar terminating short of the end of the collar, each collar having its outer end formed as a circumferentially extending inwardly depressed rib having one Wall engaging the extreme ends of the guide members associated therewith, said guide members each having a double bow providing zones on the guide members between said collars which are spaced centrally between the collars and which have casing confronting surfaces located substantially at the same radial distance from the axis as the apices of said ribs,outwardly bowed portions on said guide members extending from said end portions through apertures in said shell.

2. A casing guide as in claim 1 wherein said zones are formed as generally S-shaped lateral bends in which the central portion of the S provides said surfaces.

3. In a casing guide adapted for mounting on a well casing, the combination of a pair of circular collars axially aligned and spaced from one another, a plurality of guide members extending between said collars and each having its opposed ends connected respectively with said collars, each collar comprising a sheet metal shell of substantially uniform wall thickness having progressively inwardly stepped bands formed in the wall with the band of the greatest inside diameter at the outer end of the collar and joined to the adjacent band by a circumferential band providing an annular shoulder, the respective end por tions of the guide members lying adjacent and secured to the inside of the outer bands with the extreme ends of the guide member at each collar terminating short of the end of the collar, each collar having its outer end formed as a circumrerentially extending inwardly depressed rib having one wall engaging the extreme ends of the guide members associated therewith, said guide members having outwardly bowed portions extending from said end portions through apertures in said collars and central zones depressed toward said axis whereby to provide each guide member with a double bow, each said central zone provided with a lateral jog operable to permit resilient defor mation of said guide members in response to longitudinally applied compressive forces on the ends of the guides.

4. The combination as in claim 3 wherein the one end portion of each guide member is offset circumferentially from the other end portion.

5. The combination as in claim 4 wherein the offset is equal to one-half the spacing between the said one end portion of said guide members around the collar.

6. The combination as in claim 4 wherein said guide members each comprise bars of spring steelhaving substantial uniform cross section throughout their length.

References Cited by the Examiner UNITED STATES PATENTS 1,801,334 4/31 Dalldorf et al. '308-4 2,717,650 9/55 Hall 166-173 X 2,845,128 7/58 Clark et al. 166-241 X BENJAMIN HERSH, Primary Examiner.

CHARLES E. OCONNELL, Examiner. 

3. IN A CASING GUIDE ADAPTED FOR MOUNTING ON A WELL CASING, THE COMBINATION OF A PAIR OF CIRCULAR COLLARS AXIALLY ALIGNED AND SPACED FROM ONE ANOTHER, A PLURALITY OF GUIDE MEMBERS EXTENDING BETWEEN SAID COLLARS AND EACH HAVING ITS OPPOSED ENDS CONNECTED RESPECTIVELY WITH SAID COLLARS, EACH COLLAR COMPRISING A SHEET METAL SHELL OF SUBSTANTIALLY UNIFORM WALL THICKNESS HAVING PROGRESSIVELY INWARDLY STEPPED BANDS FORMED IN THE WALL WITH THE BAND OF THE GREATEST INSIDE DIAMETER AT THE OUTER END OF THE COLLAR AND JOINED TO THE ADJACENT BAND BY A CIRCUMFERENTIAL BAND PROVIDING AN ANNULAR SHOULDER, THE RESPECTIVE END PORTIONS OF THE GUIDE MEMBERS LYING ADJACENT AND SECURED TO THE INSIDE OF THE OUTER BANDS WITH THE EXTREME ENDS OF THE GUIDE MEMBER AT EACH COLLAR TERMINATING SHORT OF THE END OF THE COLLAR, EACH COLLAR HAVING ITS OUTER END FORMED AS A CIRCUMFERENTIALLY EXTENDING INWARDLY DEPRESSED RIB HAVING ONE WALL ENGAGING THE EXTREME ENDS OF THE GUIDE MEMBERS ASSOCIATED THEREWITH, SAID GUIDE MEMBERS HAVING OUTWARDLY BOWED PORTIONS EXTENDING FROM SAID END PORTIONS THROUGH APERTURES IN SAID COLLARS AND CENTRAL ZONES DEPRESSED TOWARD SAID AXIS WHEREBY TO PROVIDE EACH GUIDE MEMBER WITH A DOUBLE BOW, EACH SAID CENTRAL ZONE PROVIDED WITH A LATERAL JOG OPERABLE TO PERMIT RESILIENT DEFORMATION OF SAID GUIDE MEMBERS IN RESPONSE TO LONGITUDINALLY APPLIED COMPRESSIVE FORCES ON THE ENDS OF THE GUIDES. 